To provide a bitumen-containing composition having a reinforcing effect as well as a soundproofing effect and used as a coating composition used for a car body steel sheet having an effect of reducing the weight of a car body and to provide a process for producing the same.

There are provided a process for producing a bitumen-containing composition, especially, an automotive soundproofing composition, being the thermally applicable and having an acoustic effect, comprising mixing bitumen with other materials such as an adhesion medium, a polymer, a wax, and a non-crosslinkable resin at 130-180°C to form a homogeneous composition, which process comprises cooling the formed composition to a temperature of 130°C or below, and adding a thermally crosslinkable resin or a thermally crosslinkable reactant mixture to the cooled composition and a bitumen-containing composition produced thereby.